The presence of food spoilage organisms and pathogens in foods is a major concern to the food processing industry, government regulatory agencies, and consumers. Elimination of pathogenic contamination has been the subject of a great deal of study in the food industry and in the scientific community. In particular, elimination of Listeria monocytogenes has been the focus of numerous studies and articles. See, e.g., Barnes et al., Morbid. Mortal. Weekly Rep. 38:267-268 (1989). Buchanan et al, Appl. Environ. Microbiol. 55:599-603 (1989); Bailey et al., J. Food Prot. 52:148-150 (1989); Gitter, Vet. Res. 99:336 (1976); and Farber et al., Can. Inst. Food Sci. Technol. J. 21:430-434 (1988).
Although food is generally inspected prior to packaging, it is presently not practical to inspect each package of food for complete application of an antimicrobial agent to the product. Incomplete or otherwise insufficient application reduces the efficacy of the antimicrobial.
U.S. Pat. Nos. 5,573,800 and 5,573,801 provide an antimicrobial solution that includes nisin and/or pediocin along with a chelator, and processes for using the antimicrobial solution to treat the surface of foods by applying the composition to the entire surface of the food. In certain embodiments, the antimicrobial solution is contained on packaging films which are applied to foods. The antimicrobial solution is deposited on the surface by spraying, dipping, mixing, or by impregnating or coating the antimicrobial agent onto a food casing.
U.S. Pat. No. 5,085,873 provides a process for the treatment of a hydrated food product by depositing an antimicrobial mixture containing lactoperoxidase, a thiocyanate, and an oxygen donor on the surface of the hydrated food product. The antimicrobial mixture is deposited on the surface by pulverizing, immersion in a bath, or through the use of an antimicrobial agent-containing packaging.
U.S. Pat. No. 6,149,952 discloses a method for determining the presence of contaminating bacteria in a packaged food by using a permeable hydrophilic polymeric composition containing an indicator to line a package. The indicator is capable of detecting gases originating from contaminating bacteria.
Web packaging apparatus and methods using such web packaging apparatuses are well known in the food industry. U.S. Pat. Nos. 5,170,611, 5,205,110, and 5,682,729, for example, provide packaging machines for packaging food products between upper and lower webs of suitable packaging films. Generally, such packaging machines include a web transport conveyor for transporting the lower web through a series of stations, including a forming station whereby the lower web is converted into a portion of a food package, a loading station whereby the food product is loaded into the formed portion of the food package, and a closing station whereby the upper web and the formed portion of the food package containing the food product are combined to provide the packaged food product.
There remains a need for more efficient, more effective, and simplified methods for treating the surface of a food product to kill and/or significantly reduce the growth of foodborne pathogens without subjecting the food product to high temperatures for relatively long periods of time. Furthermore, there remains a need for methods to assure that an antimicrobial surface treatment is effective for essentially eliminating foodborne pathogens. The current invention provides an efficient, effective, and simplified method for controlling contamination of a food product. Furthermore, the current invention provides a simple yet surprisingly effective method for treating the surface of a food product to kill and/or significantly reduce the growth of foodborne pathogens without subjecting the food product to high temperatures for relatively long periods of time.